In magnetic disc drives, ramp load disc heads contact the disc storage media while the heads are loaded onto the media. FIG. 1 shows a schematic of a typical recording head slider 100. The slider includes a trailing edge 101 and a disc head 102. FIG. 2 shows a picture of the trailing edge corner of the center pad 103 of such a slider after a large number of load and unload cycles 200. In FIG. 2, the corner 201 has changed in height after it is worn during ramp loading. The corner 201 has worn off at approximately the angle of the static attitude of the slider. The wear is due to the large (relative to flying attitudes) pitch and roll static attitude of typical parts.
The wear shown in FIG. 2 is on the trailing edge center pad. The slider body corners can acquire similar wear under even modest roll static attitude conditions. The wafer substrate 204 becomes the greater part of the slider body 200. The head overcoat 205, typically aluminum oxide, protects the head from environmental chemical attack.
During the initial load and unload cycles, media damage can occur where the slider contacts the media. This damage can decrease as the number of load and unload cycles increases, until at some point there is no additional wear with additional cycles. At this point, the head has completely xe2x80x9crun in.xe2x80x9d
As the slider approaches the disc, there is typically no substantial air bearing effect from the corner of the slider or on the center pad because the static attitude angles are too large. There is typically no real opportunity for an air bearing to form. As the slider wears, however, a flat area 201 relative to the disc during loading can form. This flat can grow until it forms enough of an air bearing, which can result from the air compression due to the static attitude angles. This air bearing is adequate when the force on it is enough to overcome the static torque placed on the slider by the suspension. At this point, the loading on the disc becomes relatively benign because the slider can be loaded without any substantial solid-to-solid contact. If the head and disc interface has survived this long, it typically lasts indefinitely.
As in FIG. 2, the aluminum oxide 205 forming the trailing edge of the slider 202 is of finite thickness. If there is too much static attitude or too little disc speed for an air bearing to form, the aluminum oxide 205 will continue to wear until the much harder slider substrate 204 begins to contact the disc. It is desirable to minimize aluminum oxide thickness in recording head wafers to reduce cost and reduce pole tip thermal expansion. The center part of the aluminum oxide 202 is already etched away resulting in even less aluminum oxide to wear in. Therefore, it is desirable to find a way to control more effectively the ramp load and unload wear on the slider.
The present invention relates to controlling initial load and unload wear on a slider. In particular the present invention relates to a trailing edge extender for controlling initial load and unload wear on a slider.
In one aspect of this invention, a slider for supporting a transducer proximate to a recording medium is disclosed. The slider includes a trailing edge extender positioned on a trailing edge. The extender allows additional controlled wear to occur before a substrate of the slider contacts the recording medium. The trailing edge extender can be positioned at an outer corner on the trailing edge of the slider. The trailing edge extender can be positioned at a transducer pad on the trailing edge of the slider. The trailing edge extender can include a depth of the step depth, cavity depth, or air bearing surface level depth.
The slider can include a second trailing edge extender positioned on the trailing edge of the slider. This second trailing edge extender can be positioned on an opposite side of the first trailing edge extender on the trailing edge of the slider. The trailing edge can be made of a material or combination of materials such as aluminum oxide, diamond-like carbon, aluminum nitride, and silicon carbide.
In another aspect of this invention, a method for fabricating a slider for supporting a transducer proximate to a recording medium is disclosed. The method includes fabricating a trailing edge extender positioned on a trailing edge. The extender allows additional controlled wear to occur before a substrate of the slider contacts the recording medium. The fabrication of the trailing edge extender can include depositing a ridge over a dice cut. The fabrication of the trailing edge extender can also include dicing a rowbar to form a partial ridge.
The details of one or more embodiments of the invention are set forth in the accompanying drawing and the description below. Implementations can provide advantages such as improved control of the ramp load and unload wear on the slider.